The Tides Foundation, which says it promotes human rights, justice, and a healthy, sustainable environment, has come in for frequent criticism on Beck's show. A suspect in a July 28 shootout with police, Byron Williams, told police in an affidavit he had intended to go to the Tides Foundation's office in San Francisco and kill founder and Chief Executive Officer Drummond Pike.

"I would have never started watching Fox News if it wasn't for the fact that Beck was on there," Williams told the liberal blog Media Matters in a jailhouse interview. "And it was the things that he did, it was the things he exposed that blew my mind."

Pike wrote to 10 advertisers Friday urging them to pull their advertising from Fox, Ad Week reported.

"This is neither a hollow request, nor one rhetorically made," Pike wrote. "There is an urgency to it born of our own direct experience as the target of a would-be assassin inspired by Fox's Glenn Beck Show."

The gun battle on an Oakland, Calif., freeway broke out after police stopped a pickup for speeding and weaving through traffic on Interstate 580. Williams was wearing a bullet-resistant vest and was armed with a handgun, rifle and shotgun, authorities said.

"Beck tells viewers that Tides has 'funneled' money to 'some of the most extreme groups on the left;' and that our mission is to 'warp your children's brains and make sure they know how evil capitalism is,'" Pike wrote in letters to JP Morgan Chase, Geico, Zurich Financial, Chrysler, Direct Holdings Americas (Time-Life), GlaxoSmithKline, AstraZeneca, Lilly Corporate Center, BP and The Hartford Financial Services Group, Ad Week reported. "It has become clear that the only way to stop supporting Beck is to stop supporting Fox News."

Fox News did not immediately respond to a request for comment, the trade magazine said.

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